OBJDUMP(1) GNU Development Tools OBJDUMP(1)
NAME
objdump - display information from object files.
SYNOPSIS
objdump [-a|--archive-headers]
[-b bfdname|--target=bfdname]
[-C|--demangle[=style] ]
[-d|--disassemble]
[-D|--disassemble-all]
[-z|--disassemble-zeroes]
[-EB|-EL|--endian={big | little }]
[-f|--file-headers]
[-F|--file-offsets]
[--file-start-context]
[-g|--debugging]
[-e|--debugging-tags]
[-h|--section-headers|--headers]
[-i|--info]
[-j section|--section=section]
[-l|--line-numbers]
[-S|--source]
[-m machine|--architecture=machine]
[-M options|--disassembler-options=options]
[-p|--private-headers]
[-P options|--private=options]
[-r|--reloc]
[-R|--dynamic-reloc]
[-s|--full-contents]
[-W[lLiaprmfFsoRt]|
--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index]]
[-G|--stabs]
[-t|--syms]
[-T|--dynamic-syms]
[-x|--all-headers]
[-w|--wide]
[--start-address=address]
[--stop-address=address]
[--prefix-addresses]
[--[no-]show-raw-insn]
[--adjust-vma=offset]
[--special-syms]
[--prefix=prefix]
[--prefix-strip=level]
[--insn-width=width]
[-V|--version]
[-H|--help]
objfile...
DESCRIPTION
objdump displays information about one or more object files. The options control what particular information
to display. This information is mostly useful to programmers who are working on the compilation tools, as
opposed to programmers who just want their program to compile and work.
objfile... are the object files to be examined. When you specify archives, objdump shows information on each
of the member object files.
addresses do not correspond to the symbol table, which can happen when putting sections at particular
addresses when using a format which can not represent section addresses, such as a.out.
-b bfdname
--target=bfdname
Specify that the object-code format for the object files is bfdname. This option may not be necessary;
objdump can automatically recognize many formats.
For example,
objdump -b oasys -m vax -h fu.o
displays summary information from the section headers (-h) of fu.o, which is explicitly identified (-m) as
a VAX object file in the format produced by Oasys compilers. You can list the formats available with the
-i option.
-C
--demangle[=style]
Decode (demangle) low-level symbol names into user-level names. Besides removing any initial underscore
prepended by the system, this makes C++ function names readable. Different compilers have different
mangling styles. The optional demangling style argument can be used to choose an appropriate demangling
style for your compiler.
-g
--debugging
Display debugging information. This attempts to parse STABS and IEEE debugging format information stored
in the file and print it out using a C like syntax. If neither of these formats are found this option
falls back on the -W option to print any DWARF information in the file.
-e
--debugging-tags
Like -g, but the information is generated in a format compatible with ctags tool.
-d
--disassemble
Display the assembler mnemonics for the machine instructions from objfile. This option only disassembles
those sections which are expected to contain instructions.
-D
--disassemble-all
Like -d, but disassemble the contents of all sections, not just those expected to contain instructions.
If the target is an ARM architecture this switch also has the effect of forcing the disassembler to decode
pieces of data found in code sections as if they were instructions.
--prefix-addresses
When disassembling, print the complete address on each line. This is the older disassembly format.
-EB
-EL
--endian={big|little}
Specify the endianness of the object files. This only affects disassembly. This can be useful when
disassembling a file format which does not describe endianness information, such as S-records.
Specify that when displaying interlisted source code/disassembly (assumes -S) from a file that has not yet
been displayed, extend the context to the start of the file.
-h
--section-headers
--headers
Display summary information from the section headers of the object file.
File segments may be relocated to nonstandard addresses, for example by using the -Ttext, -Tdata, or -Tbss
options to ld. However, some object file formats, such as a.out, do not store the starting address of the
file segments. In those situations, although ld relocates the sections correctly, using objdump -h to
list the file section headers cannot show the correct addresses. Instead, it shows the usual addresses,
which are implicit for the target.
-H
--help
Print a summary of the options to objdump and exit.
-i
--info
Display a list showing all architectures and object formats available for specification with -b or -m.
-j name
--section=name
Display information only for section name.
-l
--line-numbers
Label the display (using debugging information) with the filename and source line numbers corresponding to
the object code or relocs shown. Only useful with -d, -D, or -r.
-m machine
--architecture=machine
Specify the architecture to use when disassembling object files. This can be useful when disassembling
object files which do not describe architecture information, such as S-records. You can list the
available architectures with the -i option.
If the target is an ARM architecture then this switch has an additional effect. It restricts the
disassembly to only those instructions supported by the architecture specified by machine. If it is
necessary to use this switch because the input file does not contain any architecture information, but it
is also desired to disassemble all the instructions use -marm.
-M options
--disassembler-options=options
Pass target specific information to the disassembler. Only supported on some targets. If it is necessary
to specify more than one disassembler option then multiple -M options can be used or can be placed
together into a comma separated list.
If the target is an ARM architecture then this switch can be used to select which register name set is
used during disassembler. Specifying -M reg-names-std (the default) will select the register names as
used in ARM's instruction set documentation, but with register 13 called 'sp', register 14 called 'lr' and
register 15 called 'pc'. Specifying -M reg-names-apcs will select the name set used by the ARM Procedure
Call Standard, whilst specifying -M reg-names-raw will just use r followed by the register number.
mode. intel-mnemonic implies intel and att-mnemonic implies att. addr64, addr32, addr16, data32 and
data16 specify the default address size and operand size. These four options will be overridden if
x86-64, i386 or i8086 appear later in the option string. Lastly, suffix, when in AT&T mode, instructs the
disassembler to print a mnemonic suffix even when the suffix could be inferred by the operands.
For PowerPC, booke controls the disassembly of BookE instructions. 32 and 64 select PowerPC and PowerPC64
disassembly, respectively. e300 selects disassembly for the e300 family. 440 selects disassembly for the
PowerPC 440. ppcps selects disassembly for the paired single instructions of the PPC750CL.
For MIPS, this option controls the printing of instruction mnemonic names and register names in
disassembled instructions. Multiple selections from the following may be specified as a comma separated
string, and invalid options are ignored:
"no-aliases"
Print the 'raw' instruction mnemonic instead of some pseudo instruction mnemonic. I.e., print 'daddu'
or 'or' instead of 'move', 'sll' instead of 'nop', etc.
"msa"
Disassemble MSA instructions.
"virt"
Disassemble the virtualization ASE instructions.
"xpa"
Disassemble the eXtended Physical Address (XPA) ASE instructions.
"gpr-names=ABI"
Print GPR (general-purpose register) names as appropriate for the specified ABI. By default, GPR
names are selected according to the ABI of the binary being disassembled.
"fpr-names=ABI"
Print FPR (floating-point register) names as appropriate for the specified ABI. By default, FPR
numbers are printed rather than names.
"cp0-names=ARCH"
Print CP0 (system control coprocessor; coprocessor 0) register names as appropriate for the CPU or
architecture specified by ARCH. By default, CP0 register names are selected according to the
architecture and CPU of the binary being disassembled.
"hwr-names=ARCH"
Print HWR (hardware register, used by the "rdhwr" instruction) names as appropriate for the CPU or
architecture specified by ARCH. By default, HWR names are selected according to the architecture and
CPU of the binary being disassembled.
"reg-names=ABI"
Print GPR and FPR names as appropriate for the selected ABI.
"reg-names=ARCH"
Print CPU-specific register names (CP0 register and HWR names) as appropriate for the selected CPU or
architecture.
For any of the options listed above, ABI or ARCH may be specified as numeric to have numbers printed
rather than names, for the selected types of registers. You can list the available values of ABI and ARCH
using the --help option.
--private=options
Print information that is specific to the object file format. The argument options is a comma separated
list that depends on the format (the lists of options is displayed with the help).
For XCOFF, the available options are: header, aout, sections, syms, relocs, lineno, loader, except,
typchk, traceback, toc and ldinfo.
-r
--reloc
Print the relocation entries of the file. If used with -d or -D, the relocations are printed interspersed
with the disassembly.
-R
--dynamic-reloc
Print the dynamic relocation entries of the file. This is only meaningful for dynamic objects, such as
certain types of shared libraries. As for -r, if used with -d or -D, the relocations are printed
interspersed with the disassembly.
-s
--full-contents
Display the full contents of any sections requested. By default all non-empty sections are displayed.
-S
--source
Display source code intermixed with disassembly, if possible. Implies -d.
--prefix=prefix
Specify prefix to add to the absolute paths when used with -S.
--prefix-strip=level
Indicate how many initial directory names to strip off the hardwired absolute paths. It has no effect
without --prefix=prefix.
--show-raw-insn
When disassembling instructions, print the instruction in hex as well as in symbolic form. This is the
default except when --prefix-addresses is used.
--no-show-raw-insn
When disassembling instructions, do not print the instruction bytes. This is the default when
--prefix-addresses is used.
--insn-width=width
Display width bytes on a single line when disassembling instructions.
-W[lLiaprmfFsoRt]
--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges,=gdb_index]
Displays the contents of the debug sections in the file, if any are present. If one of the optional
letters or words follows the switch then only data found in those specific sections will be dumped.
Note that there is no single letter option to display the content of trace sections or .gdb_index.
Note: the output from the =info option can also be affected by the options --dwarf-depth, the
--dwarf-start and the --dwarf-check.
This can be used in conjunction with --dwarf-depth.
--dwarf-check
Enable additional checks for consistency of Dwarf information.
-G
--stabs
Display the full contents of any sections requested. Display the contents of the .stab and .stab.index
and .stab.excl sections from an ELF file. This is only useful on systems (such as Solaris 2.0) in which
".stab" debugging symbol-table entries are carried in an ELF section. In most other file formats,
debugging symbol-table entries are interleaved with linkage symbols, and are visible in the --syms output.
--start-address=address
Start displaying data at the specified address. This affects the output of the -d, -r and -s options.
--stop-address=address
Stop displaying data at the specified address. This affects the output of the -d, -r and -s options.
-t
--syms
Print the symbol table entries of the file. This is similar to the information provided by the nm
program, although the display format is different. The format of the output depends upon the format of
the file being dumped, but there are two main types. One looks like this:
[ 4](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x00000000 .bss
[ 6](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000 fred
where the number inside the square brackets is the number of the entry in the symbol table, the sec number
is the section number, the fl value are the symbol's flag bits, the ty number is the symbol's type, the
scl number is the symbol's storage class and the nx value is the number of auxilary entries associated
with the symbol. The last two fields are the symbol's value and its name.
The other common output format, usually seen with ELF based files, looks like this:
00000000 l d .bss 00000000 .bss
00000000 g .text 00000000 fred
Here the first number is the symbol's value (sometimes refered to as its address). The next field is
actually a set of characters and spaces indicating the flag bits that are set on the symbol. These
characters are described below. Next is the section with which the symbol is associated or *ABS* if the
section is absolute (ie not connected with any section), or *UND* if the section is referenced in the file
being dumped, but not defined there.
After the section name comes another field, a number, which for common symbols is the alignment and for
other symbol is the size. Finally the symbol's name is displayed.
The flag characters are divided into 7 groups as follows:
"l"
"g"
"u"
"!" The symbol is a local (l), global (g), unique global (u), neither global nor local (a space) or both
global and local (!). A symbol can be neither local or global for a variety of reasons, e.g., because
"I"
"i" The symbol is an indirect reference to another symbol (I), a function to be evaluated during reloc
processing (i) or a normal symbol (a space).
"d"
"D" The symbol is a debugging symbol (d) or a dynamic symbol (D) or a normal symbol (a space).
"F"
"f"
"O" The symbol is the name of a function (F) or a file (f) or an object (O) or just a normal symbol (a
space).
-T
--dynamic-syms
Print the dynamic symbol table entries of the file. This is only meaningful for dynamic objects, such as
certain types of shared libraries. This is similar to the information provided by the nm program when
given the -D (--dynamic) option.
--special-syms
When displaying symbols include those which the target considers to be special in some way and which would
not normally be of interest to the user.
-V
--version
Print the version number of objdump and exit.
-x
--all-headers
Display all available header information, including the symbol table and relocation entries. Using -x is
equivalent to specifying all of -a -f -h -p -r -t.
-w
--wide
Format some lines for output devices that have more than 80 columns. Also do not truncate symbol names
when they are displayed.
-z
--disassemble-zeroes
Normally the disassembly output will skip blocks of zeroes. This option directs the disassembler to
disassemble those blocks, just like any other data.
@file
Read command-line options from file. The options read are inserted in place of the original @file option.
If file does not exist, or cannot be read, then the option will be treated literally, and not removed.
Options in file are separated by whitespace. A whitespace character may be included in an option by
surrounding the entire option in either single or double quotes. Any character (including a backslash)
may be included by prefixing the character to be included with a backslash. The file may itself contain
additional @file options; any such options will be processed recursively.
SEE ALSO
nm(1), readelf(1), and the Info entries for binutils.
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